#define _CRT_SECURE_NO_WARNINGS 1

#include <stdio.h>

int main()
{
	int arr[10] = { 1,3,5,7,9,4,6,2,8,0 };
	int i = 0, j = 0;
	int sz = sizeof(arr) / sizeof(arr[0]);
	for(i=0;i<sz-1;i++)
		for(j=0;j<sz-1;j++)
			if (arr[j] > arr[j + 1])
			{
				int tmp = arr[j];
				arr[j] = arr[j + 1];
				arr[j + 1] = tmp;
			}
	for (i = 0; i < sz; i++)
		printf("%d ", arr[i]);
	return 0;
}

#include <stdio.h>

int fact(int n)
{
	int i = 0;
	int ret = 1;
	for (i = 1; i <= n; i++)
	{
		ret *= i;
	}
	return ret;
}

int main()
{
	int m = 0, n = 0;
	scanf("%d %d", &m, &n);
	printf("%d\n", fact(m) / (fact(m - n) * fact(n)));
	return 0;
}